Lifting jack



Nov. 11, 1941. M. B. QLUCKER LIFTING JACK Filed Oct. 13, 1939 IN VENTOR. Mal/01d BMr 3w 2 Sheets-Sheet l A TTORNEYfi Nov. 11, 1941. M. B. LUCKER LIFTING JACK Filed Oct. 13, 1939 2 Sheets-Sheet 2 v 2 E m Qfi MH 9w w HQ 2 H11 MN ha NM .2 J

mm mm W Q. g v 2 l m kw atented Nov '11, 1941 1 STATES Lm'rmc men Application October 13, 1939, Serial No. 299,33d

. 21 Claims.

The invention relates to lifting jacks, and particularly to jacks of the friction gripping clamp or cam type.

It is an object of the invention to provide .a friction clamp or cam lifting jack of improved construction and operating characteristics, and particularly to provide improved means and methods for effecting the lowering or release movements of the jack load-lifting member.

More specifically, it it an object of the invention to provide a friction clamp or cam lifting jack wherein the lowering or release movements of theload-lifting member are under the control of the jack actuating lever, the actuating lever being operable to efiect the release or lowering of the lifting member while maintaining control of the member at all times whereby to effect the controlled lowering of the load.

A further object of the invention is to provide a friction clamp or cam lifting jack wherein the lowering or release of the load-lifting member is controlled by means of the actuating clamp or cam.

A still further object of the invention is to provide readily operable means for moving the holding clamp or cam intoinoperativeposition and for maintaining it in such position during load-lowering operations.

Various other objects, advantages and features of the invention will appear from the following specification when'taken in connection with the accompanying drawings wherein certain preferred embodiments of the invention are set forth for purposes of illustration."

In the drawings, wherein like reference numerals refer to like parts throughout:

Fig. l is a general si'de'assembly view of a lifting jack constructed in accordance with one preferred form of the invention.

Fig. 2 is a front view of the jack structure shown in Fig. I, particularly illustrating the lifting body and its associated parts. 4

Figs. 3, 4, and 6' are side sectional views through the jack structure of Figs. 1 and 2 showing the position of the parts in various operating positions, Figs. 3 and 4 showing the position of the parts during load-raising operations and Figs. 5 and 6 showing the position of the parts during load-lowering movements.

. Figs. 7 and 8 are partial side and front views respectively of a modified form of construction. and

Figs. 9 and 10 are partial side illustrating still further modified forms of tur'es embodying the invention.

Referring more particularly to the drawings, and first to the embodiment illustrated in Figs. 1 to 6 inclusive, the structureshown is of the strucgeneral type illustrated in my copencling applisectional [views cation Serial No. 184,174, filed January 10, 1938, patented December 31, 1940, as Patent 2,227,396, entitled Automobile jack. The structure comprises an upstanding circular shaft ill carried in any suitable manner on a base H which is adapted to rest upon the ground or other supporting surface. A main lifting body i2 is mountedfor longitudinal sliding movement along the shaft w the raising or lowering movements of the lifting body being under the control of friction clamps or cams, later to be described.

The lifting body may conveniently be formed as a one-piece castingprovided with a central bore through which the shaft I0 is adapted .to'

bumper of an automotive vehicle as illustrated .by the reference numeral l6. While the lifting jack illustrated is thus of the automobile bumper jack type,-it isto be understood that the prin-.

' ciples of the present invention may be adapted to lifting jacks and related structures of other types and kinds, and adapted for other purposes.

The lower edge of the load-engaging collar arranged to seat upon an annular bead' ll .formed on the lifting body, and the cylindrical body portion I3 is formed at itsupper end with a projection. I8 adapted to prevent the inadvertent dislodgementof the load-enga n collar in the event that the jack structure is inverted,

as when not in use.

Referring more particularly to Fig. 3, it will be seen that the lifting body is provided with .a pair of transverse partitions Z0 and 2|. partition 20 cooperates with an enlarged head portion 22 formed on the upper end'of the shaft l0 whereby to prevent the projection of the lifting body.upwardly off of the end of the shaft. The partition 2| separates the lower portion of the lifting body into. lower and upper chambers 23 and 24 in which the actuating and holding clamps or cams 25 and 26 are respectively mounted. The clamps are provided with central openings through which the shaft l0 projects,

brought into gripping or looking engagement with the shaft as the clamps are canted. The

arrangement is such that when the clamps are in uncanted position the clamps are free to move longitudinally relative to the shaft, but when the The A compression spring 30 encircling the shaft bears against the lower surface of the actuating clamp 25,'and normally holds it in uncanted position, as seen in Fig. 3, in seated engagement against the lifting body barrier wall 2|, the clamp being so shaped and proportioned that it is in uncanted position when seated against the barrier wall. A compression spring 3| also encircling the shaft l bears against the lower surface of the holding clamp 26 and normally urges it counterclockwise as seen in Fig. 3 into gripping engagement with the shaft. One end 32 of the holding clamp is loosely engaged within an opening 33 in the lifting body, the engagement 32-33 thus constituting a pivotal connection between the lifting body and holding clamp whereby the clamp may be moved counterclockwise into gripping engagement with the shaft by the compression spring. The lower end of the compression spring 3| seats against the barrier wall 2|, whereas the lower end of the compression spring 30 seats upon the extreme lower surface 34 of the lifting body.

other words, the upward thrust of the compression spring 3| is inoperative to move the lever from its release position. The release lever is also preferably provided with an engagement surface 50 which cooperates with an abutment to limit the counterclockwise lever movement.

In the operation of the structure, the shaft I0 is first placed upon the base II, and the lifting body I2 is then pushed upwardly into engagement with' the load, the load-engaging collar l4 first being rotated into proper load-engaging position. The lifting body may be readily moved upwardly into engagement with the load, as the actuating and holding clamps do not inhibit such movement when in canted or uncanted position.

With the load properly engaged, and assuming the release lever 43 to be in its inoperative position as shown in Fig. 3, the main operating lever 35 is then actuated to effect the step by step raising of the lifting body along the shaft 0. As the operating lever is moved counterclockwise w from its Fig. 3 to its Fig. 4 position, the actuating As best shown in Fig. 1, an operating lever 35 is pivotally mounted upon the lifing body, on a pivot pin 36, the inner end of theoperating l'ever being provided with a pair of toothed projections 31 and 38, Fig. 3, engage'able on opposite sides of the actuating clamp 25. The pivot pin 36 is mounted in a pair of laterally projecting ears 39 and 40, Fig. 2, formed on the lifting body and de fining a front lifting body opening 4|. The operating lever is also provided with an extension 42, which is preferably in the form of a removable bar adapted to be received within a socket portion on the operating lever. The bar 42 may be of any suitable length to provide the necessary leverage in the operation of the lever. In accordance with the invention, the operating lever controls the movements of the actuating clamp to effect both the raising and lowering of the lifting body along the shaft I0, as will be later more particularly described. Also in accordance with the invention. means is provided for disabling the action of the holding clamp 26 during the lowering movements of the lifting body.

This disabling means comprises a manually operable release lever 43 pivotally mounted upon the lifting body by means of a pivot pin 44, the pivot .pin being carried in a pair of small ears 45 and 46, Fig. 2, projecting laterally from the lifting body. The lower end of the release lever is adapted to engage the end portion 41 of the holding clamp, which end portion projects outwardly from the lifting body through the opening 4|. The extreme end of the projecting clamp portion 41 is provided with a raised lug 48 upon which the end of the release lever is adapted to seat when moved to the positions shown in Figs. 5 and 6 of the drawings. When the release lever is in inoperative position, as shown in Figs. 3 and 4, the holding clamp 25 will be maintained in gripping engagement with the shaft by the compression spring 3|. When the release lever is moved to release or operative position as shown in Figs. 5 and 6, the holding clamp will be forced downwardly or clockwise against the action of the compression spring, thereby moving the clamp to uncanted or release position. After the manual movement of the release lever to the positions substantially through the axis of the pivot 44. In

clamp 25 will first be canted clockwise into gripping engagement with the shaft upon the initial movement of the lever, and thereafter serve as l a reaction base upon which the inner end of the lever may be fulcrumed enabling the lever to raise the lifting body by means of the pivot pin 36. Fig. 3 shows the position of the parts prior to movement of the operating lever, and Fig. 4 shows the position of the parts at the end of the operating stroke. During the upward movement of the lifting body, the holding clamp 26 is constantly maintained in counterclockwise gripping position. The canted position of the holding clamp does not prevent the upward movement of the lifting body, but does prevent any retrograde or downward movement, the holding clamp thus serving to retain the lifting body to any position to which it has been raised. As the operating lever 35 is restored from its Fig. 4 to its Fig. 3 position, the actuating clamp is moved upwardly to a new position of engagement upon the shaft by the compression spring 30, and in the event the clamp should tend to stick, the tooth projection 31 on the operating lever positively engages and releases the clamp. The operation may be repeated to effect the step by step lifting of the load to the desired amount.

To effect the controlled lowering of the load, the operating lever is moved from its normal or release position as shown in Fig. 3, to some intermediate operating position, for example as shown in Fig. 5, wherein the actuating clamp is moved away from the barrier wall 2| and brought into gripping engagement with the shaft. A slight raising of the lifting body takes place during this operation. With the actuating clamp thus in canted position and serving as a support means for the lifting body, the release lever 43 is then manipulated to its release position as shown in Figs. 5 and 6. This movement of the release lever uncants the holding clamp and completely releases this clamp, but so long as the operator maintains the main actuating lever 35 in position, the lifting body will be prevented from any lowering movement. With the holding clamp released the operator then moves the lever 35 to the position shownin Fig. 6 wherein the actuating clamp is still in canted or gripping position but is in immediate juxtaposition to the barrier wall 2|. Any further clockwise or lowering movement of the lever 35 will cause the actuating clamp to become seated against the barrier wall and thereby be uncanted and released from gripping engagement with the shaft, causing the lowering of the lifting body under the weight of the load. However, immediately as the lifting body is lowered, the operating lever 35 will again be moved counterclockwise causing the actuating clamp to be moved from the barrier wall and again brought into gripping engagement with at all times under the operator's full control and may be stopped immediately and automatically at any time merely by stopping the downward movement of the operating lever.

It will be seen that the invention thus provides, in a friction clamp or cam lifting jack, for the raising and lowering of the load from a single operating lever, the raising and lowering movements being at all times under full control of the operator.

In Figs. 7, 8, 9 and 10 alternate means are illustrated for efiecting the release of the holding clamp and for maintaining it in release position during the lowering of the load. In Figs. 7 and 8 a horizontally disposed screw 55 is provided threaded into a lug 56 formed as a part of the lifting body. The conical end 51 of the screw is adapted to engage and depress the end ti of the holding clamp as the screw is threaded inwardly, to the left as seen in Fig. 8. The screw may be operated by hand, or if desired a suitable 'slot such as indicated at 58 may be provided in the screw head portion to facilitate manipulation by a suitable tool such as a screw-driver or the like. In Fig. 9 a similar release screw 60 is illustrated engageable with the end of the holding clamp, only in this instance the screw is substantially vertically disposed and is threaded into a lug portion 6| formed on the lifting body. In

. Fig. 10 the release screw 62 is threaded into the cross portion of a substantially U-shaped bracket 63 formed as part of the lifting body. The operation of the constructions as illustrated in Figs.

7, 8, 9 and 10 is similar to that previously described in reference to Figs. 1 to 6 inclusive, the

release screws being utilized in substitution for the release lever 43 to effect the movement of the holding clamp to release position and the maintenance of the clamp in such position during the load-lowering operation.

An alternate. method of operating the foregoing jack structures is to effect the lowering of the'lifting body under the control of the holding clamp by moving the holding clamp into inoperative position while the actuating clamp remains inoperative and seated against the baffle wall 2!, as shown for example in Fig. 3. In accordance with this method of operation the actuating lever 35 is permitted" to remain in the .position illustrated in Fig. 3, and the release devices 43, 55, 60, or 52 then operated, preferably slowly, to release the holding clamp and lower'the load.

The structures of Figs. '7, 8,9 and 10 are particularly adapted to this mode of operation as the screw members provide an accurate control for the movements of the holding clamp. However. it is preferred to effect the lowering operation by means of the actuating clamp, as previously described, whereby to insure the positive and accurate control of the movements of the lifting body during the lowering operation.

This application is a continuation-in-part of my copending application Serial No. 74,969, filed April 17, 1936, patented March 18, 1941 as Patent 2,234,970, and entitled "Lifting jack.

It is obvious that various changes may be made in the specific embodiments of the invention set forth for purposes of illustration without departing from the spirit thereof. Accordinglythe invention is not to be limited to the specific embodiments shown and described, but only as indicated in the following claims.

The invention is hereby claimed as follows:

1. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the base comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, an operating member for controlling the movements of the actuating clamp, and means mounted as a part of the jack structure for disabling the holding clamp, the operating member being operableto manipulate the actuating clamp when the disabling means is inactive to controllably operate the load-engaging member in one direction and when the disabling means is activeto manipulate the actuating clamp to controllably operate the load-engaging member in the opposite dibeing an actuating clamp and the other of the clamps being a holding clamp, an operating member for controlling the movements of the actuating clamp, means movable to'an active position for disabling the holding clamp, said disabling means being self-holding to maintain the holding clamp disabled when moved to active i position, and the operating member being operable to manipulate the actuating clamp when the disabling means is inactive to controllably operate the load-engaging member in one direc-- tion and when the disabling means is active-to manipulate the actuating clamp to controllably operate the load-engaging member in the opposite direction.

' 3. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longiing the lifting body along the shaft comprising a pair of friction clamps adapted to clampingly Gengage the shaft, one of said clamps being an 60 actuating clamp and the other of the clamps being a holding clamp, an operating member for controlling the movements of the actuating clamp, and means mounted as a part of the jack structure for disabling the holding clamp, the operating member being operable to manipulate the actuating clamp when the disabling means is inactive to controllably operate the lifting body in one direction and when the disabling means is active to manipulate the actuating clamp to controllably operate the lifting body in the opposite direction.

4. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the base compris- 75 ing a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a spring for urging the holding clamp into holding position, an operating member for controlling the movements of the actuating clamp, and disabling means for moving the holding clamp to inoperative posistantly operable during the raising operations to maintain the load-engaging member in the position to whichit is raised, and disabling means tion against the action of said spring, the operating member being operable to manipulate the actuating clamp when the holding clamp is in holding position to controllably operate the loadengaging member in one direction and when the holding clamp is inoperative to manipulate the actuating clamp to controllably operate the loadengaging member in the opposite direction.

5. A lifting jack comprising a base, an upstanding shaft mounted thereon, a lifting body including a load-engaging. member longitudinally movable upon the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps adapted to clampingly engage the shaft, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a spring for urging the holding clamp into holding position, an operating member for controlling the movements of the actuating clamp, disabling means mounted as a part of the jack structure for moving the holding clamp to inoperative position against the action of the spring, said disabling means being self-holding when moved to hold the holding clamp in inoperative position, the operating member being operable to manipulate the actuating clamp when the holding clamp is in holding position to controllably operate the loadengaging member in one direction and when the holding clamp is inoperative to manipulate the actuating clamp to controllably operate the loadengaging member in the opposite direction.

6. A lifting jack comprising a base, a loadengaging member, means for moving the loadengaging member relative to the base comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a spring for urging the holding clamp into holding position, a relatively fixed positioning member against which the actuating clamp is adapted to be seated in inoperative position, a spring for urging the actuating clamp into engagement with the positioning member, an operating member for controlling the movements of the actuating clamp, and disabling means for moving the hold ing clamp to inoperative position against the action of its spring, the operating member being operable to manipulate the actuating clamp when the holding clamp is in holding position to operate the load-engaging member in one direction and when the' holding clamp is in operative position to operate the load-engaging member in the opposite direction.

'7. A lifting jack comprising a base, a load-engaging member, means for moving the load-engaging member relative to the base comprising a pair of friction clamps, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a spring for urging the holding clamp into holding position, a relatively fixed positioning member against which the actuating clamp is adapted to engage to be positioned in inoperative position, a spring for urging the actuating clamp into engagement with the positioning member, an operating member adapted to manipulate the actuating clamp to effect the step by step raising of the load-engaging member, the holding clamp being confor moving the holding clamp to inoperative position and for maintaining it in inoperative position, the operating member being operable when the disabling means is active to move the actuating clamp against and away from the positioning member .whereby to move the actuating clamp between operative and inoperative positions to effect the controlled lowering of the load-engaging member.

8. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally slidable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps adapted to clampingly engage the shaft, one of the clamps being an actuating clamp and the other clamp being a holding clamp,

a spring for urging the holding clamp into holding position, a positioning member against which "the actuating clamp is adapted to engage to be positioned in inoperative position, a spring for urging the actuating clamp into engagement with the positioning member, an operating member adapted to manipulate the actuating clamp to effect the step by step raising of the lifting body, the holding clamp being constantly operable during the raising operations to maintain the lifting body in the position to which it is raised, and disabling means for moving the holding clamp to inoperative position and forimaintaining it in inoperative position, the operating member being operable when the disabling means is active to move the actuating clamp against and away from the positioning member whereby to move the actuating clamp between operative and inoperative -positions to effect the controlled lowering of the lifting body.

9. A lifting jack comprising a base, an upstanding shaft mounted thereon, a lifting body including a load-engaging member longitudinally slidable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps mounted within the lifting body adapted to clampingly engage the shaft, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a compression spring encircling the shaft for moving the holding clamp to holding position, a positioning wall fixed to the lifting body against which the actuating clamp is adapted to be engaged to be moved to inoperative position, a compression spring encircling the shaft for urging the actuating clamp into engagement with the positioning wall, an operating lever pivoted to the lifting body and engageable with the actuating clamp for moving it away from the positioning wall and into tilted operative position against the action of its spring, and dsabling means carried by the lifting body for moving the holding clamp to untilted inoperative position and for maintaining it in such position.

10. A lifting jack as defined in claim 13 wherein the disabling means comprises a lever pivotally mounted upon the lifting body.

11. A lifting jack as defined in claim 13 wherein the disabling means comprises a screw threadedly carriedby the lifting body.

12. In a lifting jack of the friction grip type, an elongated shaft, a body embracing the shaft, said body and shaft being relatively movable, a holding clamp anchored to the body and embracing the' shaft, said holding clamp being normined position wherein it controls continued relative movement between said shaft and body.

13. In a lifting jack of the friction grip type, an elongated shaft, a body embracing the shaft, said body and shaft being relatively movable, a holding clamp anchored to the body and embracing the shaft, said holding clamp being normally canted to prevent relative movement between the body and shaft in one direction, and release means for uncanting the holding clamp to allow such movement, said release means including an adjustable screw threaded member.

14. In a lifting jack of the friction grip type, an elongated shaft, e, body embracing the shaft, said body and shaft being relatively movable, a holding clamp anchored to the body and embracing the shaft, said holding clamp being normally canted to prevent relative movement between the body and shaft in one direction, and release means for uncanting the holding clamp to allow such movement, said release means including an adJustable screw threaded member threaded into said body and having a portion engageable with said clamp.

15. A lifting jack comprising a base, an upstanding shaft mounted on the base, a lifting body including a load-engaging member longitudinally movable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamps adapted to clampingly engage the shaft, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a spring-for urging the holding clamp into holding position in canted gripping'engagement with the shaft, disabling means for uncanting the holding clamp against the action of said spring, an operating lever pivotally mounted on the lifting body and operatively associated with the actuating clamp for moving it into canted gripping engagement with the shaft, and abutment means associated with the lifting body and engageable with the actuating clamp as the operating lever is pivoted downwardly to move the clamp into uncanted position.

116. A lifting jack comprising a base, an upstanding shaft mounted thereon, a lifting body including a load-engaging member longitudinally slidable on the shaft, means for moving the lifting body along the shaft comprising a pair of friction clamp devices mounted within the lifting body adapted to clampingly engage the shaft, one of said clamps being an actuating clamp and the other of the clamps being a holding clamp, a compression spring encircling the shaft for moving the holding clamp about a fixed fulcrum on the lifting body to shaft grippi g holding position, disabling means carried by the lifting body for disabling the holding clamp against the action of said spring, a positioning member associated with the lifting body against which the actuating clamp is adapted to be engaged in inoperative position. a compression spring encircling the shaft for urging the actuating clamp into engagement with the positioning member, and an operating lever pivoted to the lifting body, said operating lever being operable to effect both the lifting and the lowering movements' of the lifting body. 4

17. A lifting jack comprising a base, an upstanding shaft mounted thereon, a lifting body including a load-engaging member longitudinally slldable on the shaft, means for moving the lifting body along the shaft through a given range of lifting travel comprising a pair of friction clamps mounted within the lifting body and adapted to embrace the shaft, spring means associated with each of said clamps and adapted to urgethe clamps into a predetermined position, and means for lowering the lifting body comprising disabling means mounted in permanent association with one of said clamps and adapted to operatively engage said clamp and move the same to inoperative position against the action of its associated spring means, and a pivotally mounted lever, said lever being operatively associated with the other of said clamps, and the spring means associated with said other clamp being arranged to urge said other clamp into gripping engagement with the shaft while the first clamp is disabled by the disabling means,

whereby as said lever is moved a controlled lowering movement of the lifting body will be effected.

18. A lifting Jack comprising a base,,an upstanding shaft mounted thereon, a lifting body including a load-engaging member longitudinally slidable on the shaft, means for moving the lifting body along the shaft through a given range of lifting travel comprising a pair of friction clamps mounted within the lifting body and adapted to embrace the shaft, spring means associated with each of said clamps and adapted to control the operative functioning thereof, the spring means associated with one of said clamps being a coiled compression spring loosely mounted on the shaft, means including a manually operable member carried by the lifting body and shiftable to a plurality of adjusted positions to control the operative functioning .of the other of said clamps, and a pivoted operating lever for controlling the movements of said first clamp, said pivoted operating lever being adapted to effect the upward movement of the lifting body along said shaft when said manually operable member is in one adjusted position, and to effectdownward movement of the lifting body along said shaft when the manually operable member is in another of its adJusted positions.

19. A lifting Jack as defined in claim 17 wherein the lifting body is of elongated construction axially of the shaft, and wherein the load-engaging member is disposed at the upper end of the lifting body, and said friction clamps are disposed within the body below the load-engaging member.

20. A lifting jack as defined in claim 17 wherein the lifting body is of elongated construction axially of the shaft, wherein the load-engaging member is disposed at the upper end of the lifting body, and said friction clamps are disposed within the body below the load-engaging member, and wherein said lever is pivotally mounted on the lifting body and projects radially outwardly throughan opening formed in said lifting body.

21.- A lifting jaclr as defined in claim 17 wherethereof.

MILLARD B. LUCKER.

CERTIFICATE or CORRECTION. 6 Patent No. 2,262,};29. November 11, 191 1.

- MILLARD B. woman.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 10, for "it it" read -it is"; page 5, second column, line 14.1, after "means" insert --mounted as apart of the jack structure-; page i )4, second column, lines 65 and 68, claims 10 and 11 respectively, for the claim reference numeral "15'' read --9--; and that the saidLetters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of April, A. D. 19l 2.

. Henry Van Arsdale, (seal) 4 Acting Commissioner. of Patents. 

